1. Field of the Invention
The present invention generally relates to an ink jet recording apparatus using an ink jet recording head. More specifically, the present invention is directed to an ink jet recording apparatus capable of recording a color image on a recording medium without ink blurring by thinning the image by excluding some of ink dots.
2. Description of the Prior Art
A color ink jet recording apparatus ejects a plurality of ink droplets onto a recording medium to form a single pixel. A color image may be formed by varying the sort of ejecting ink. This conventional ink jet recording apparatus records on the recording medium at high speed using, for example, low viscosity ink (mainly containing water). Extremely high ink absorbing speed and absorbing capacity are required to the recording medium. Various sorts of coated paper for ink jet recording purposes have been developed which have thick ink absorbing layers. However, the ink absorbing speed and the absorbing capacity of this coated paper do not meet the requirements of the color recording using four different color inks. Accordingly, the ink blurs at the edge of the color, boundary among different colors, and high density area, so that printing sharpness is lowered and ink concentration happens to fluctuate.
On the other hand, in view of cost, curling, weights and so on, a recording medium with thin coat layer and a recording medium of plain paper are preferable. However, when a color image is recorded on such recording paper, the ink blurs conspicuously. The bleeding of ink occurs at the color mixture portion on the plain paper and the plain paper cockles. The quality of the image is debased by the contacts of the ink ejecting surface of the rcording heads with the paper while the heads are moving. Furthermore, the ink is offset by the paper transporting roller, so that the quality of the image is debased. A similar problem occurs on OHP film having low ink absorbing capacity. There are some problems, taking account of the properties of the recording head. The ink on the convex portion of the recording material is attached on the ink ejecting plane of the recording head, which cause no ink to be ejected from the ink ejecting ports. In addition, the water repellent effect of the ink ejecting plane would be weakened due to sliding between the convex portion and the recording head, so that the ink may be readily attached to the ink ejecting planes.